Relays are used to separate two different voltage levels. A PLC could be used to regulate the functioning of a 2,300V or 4,160V medium-voltage motor. While the PLC controls the relay, it is used to energise the starter, which then switches the motor voltage.
Programmable relays combine the advantages of a PLC with a lower level of complexity and expense. In instances where fewer I/O points are required, programmable relays are employed. Smart relays are capable of performing a wide range of activities, including counting, timing, and real-time clock functions.
PLCs are far more dependable and troubleshooting is lot easier. Relays' mechanical functionalities simply wear out with time. Furthermore, the wiring required to operate a relay system is far more complicated than that required to operate a PLC system. Due to additional labour costs, this may result in increased installation and upgrade charges.
The basic functions of both a relay and a PLC are the same: to control electro-mechanical equipment in the workplace. Simple operations, like as starting/stopping an electric motor after detecting an overload or malfunction, can be accomplished by both efficiently.
